Add new Bs2f1420Gamma decfile
This is based on the similar Bs_phigamma=HighPtGamma,DecProdCut decfile and uses PHSP for the decay of the f1(1420)
This is based on the similar Bs_phigamma=HighPtGamma,DecProdCut decfile and uses PHSP for the decay of the f1(1420)